1. Field Of The Invention
The present invention relates to a process for producing concentrated liquid detergent compositions containing the magnesium salt of alkyl benzene sulfonic acid and a suds boosting alkanolamide component, and which compositions have decreased viscosity during manufacture and upon cooling.
2. Description Of The Prior Art
Typical liquid dishwashing detergents contain substantial amounts of anionic surfactants that help provide greasy soil removal. Generally, the grease cutting ability of the composition increases with an increased concentration of surfactants; however, the viscosity of compositions containing concentrations of anionic surfactants of about 30-50% is potentially problematic in the manufacture of such compositions, particularly as the surfactant levels of such compositions approach 50%.
The viscosity of a liquid detergent composition is affected by the concentration of anionic surfactant components as well as all other solid ingredients. The word "solid" is used herein to refer to all ingredients other than solvents and thus may include normally liquid ingredients. A viscosity of about 12,000 cps renders a composition thick and paste-like and is thus extremely difficult to mix.
It is sometimes desirable in manufacturing liquid detergents to make a base composition separately from the finished product. The base composition contains appropriate amounts of the surfactant active ingredients such as, for example, magnesium alkylbenzene sulfonate, alkyl sulfate and alkyl ethoxy sulphate; suds boosting agents such as, for example, alkyl mono- or di-alkanolamide; and a liquid carrier such as, for example water, a water soluble solvent or mixtures of water and a water-soluble solvent. The base composition may be diluted to form the desired final liquid detergent product composition with other aqueous or aqueous-alcohol solutions containing ingredients such as, for example, hydrotropes, to provide phase stability and lower the viscosity of the composition, alkali metal salts such as, for example, magnesium sulfate or sodium sulfate to boost detergency; minor ingredients such as, for example, opacifying agents; color stabilizers; dyes; perfumes; heavy metal chelating agents; antioxidants; antimicrobial agents; etc.; and pH modifying bases and acids such as, for example, NaOH and HCl. Examples of hydrotropes include, but are not limited to, urea, C.sub.2 -C.sub.4 alcohols, sodium xylene sulfonate, potassium xylene sulfonate, sodium cumene sulfonate, ammonium xylene sulfonate and the like. Such base compositions may contain higher concentrations of surfactants and other solid ingredients than the final liquid detergent product composition and as such, the viscosities of such compositions may require expensive and high energy mixing devices during manufacture and may cause the compositions to gel at ambient temperature.
In U.S. Pat. No. 4,169,076 a method is disclosed for making a pre-neutralized base solution of the magnesium salt of an anionic active agent which can be directly utilized in the production of liquid detergent. Similarly, U.S. Pat. No. 4,129,515 discloses a process for producing a heavy-duty liquid detergent base composition wherein an anionic surfactant in the free acid form is mixed with magnesium hydroxide to provide an acid solution that is later neutralized with alkanolamine.
It is accordingly an object of this invention to provide a process for the manufacture of concentrated liquid detergent base, useful in the manufacture of concentrated liquid detergents, which comprises magnesium alkylbenzene sulfonate and alkanolamide, and in which the base is made separately from the finished product.
It is another object of this invention to provide a process for the manufacture of concentrated liquid detergent compositions that contain levels of magnesium alkylbenzene sulfonate, alkanolamide or an ethoxylated alkanolamide and other solid (non-solvent) ingredients that otherwise would result in viscosities above about 12,000 cps during manufacture or after cooling and which does not require special heavy duty or high shear mixing devices.
Another object of this invention is to provide a process for the manufacture of concentrated liquid detergent compositions containing at least about 40% solid ingredients including magnesium alkylbenzene sulfonate and a suds boosting agent including an alkanolamide or an ethoxylated alkanolamide and that can be stored at ambient temperature without gelling.